[FIX] account: invoiced amount

- Create 2 companies: A is parent of B.
- Demo is in Company A
- Create 2 invoices for a partner: one in A, one in B (100 each)
- Validate the invoices

Connected as Demo, the 'Invoiced' amount on the partner form view (stat
button) is 100, while clicking on it shows both invoices (total of 200).

There is no need to manually add the company in the `where` clause since
the `_apply_ir_rules` will take care of adding the appropriate
multi-company rules.

opw-772479